A non-invasive thermometry approach for monitoring core (internal) tissue temperature using microwave radiometry is presented. We detail the design and analyses of a microwave antenna capable of detecting core temperature at depth. Performance of the radiometer with a printed dipole antenna is evaluated at frequency of 1.4 GHz in a multilayer 3D computational structure consisting of skin, fat, and muscle. To study this approach, a human tissue model was constructed with skin, fat, and deep muscle tissues having electrical properties at working frequency of 1.4 GHz. One of the main challenges is the Radio Frequency (RF) interface; hence, frequency selection will be important. Moreover, the antenna must be designed for characteristics in close proximity of biological medium in the selected frequency band. The Specific Absorption Rate (SAR) and volume loss density have been used to determine the amount of absorbed power in each tissue layer and thus emitted power from each tissue layer. This approach has been designed to detect thermal emissions radiated from tissue up to 23 mm deep. We present the numerical analysis of 3D tissue-layer power emission and temperature sensing by a microwave radiometric antenna from a single frequency band of 1.4 GHz. Computed results show that this method senses the internal temperature in each tissue layer.
2. Haugk, M., P. Stratil, F. Sterz, D. Krizanac, C. Testori, T. Uray, J. Koller, W. Behringer, M. Holzer, and H. Herkner, "Temperature monitored on the cuff surface of an endotracheal tube reflects body temperature," Critical Care Medicine, Vol. 38, No. 7, 1569-1573, Jul. 2010.
3. Moran, J. L., J. V. Peter, P. J. Solomon, B. Grealy, T. Smith, W. Ashforth, M. Wake, S. L. Peake, and A. R. Peisach, "Tympanic temperature measurements: Are they reliable in the critically ill? A clinical study of measures of agreement," Critical Care Medicine, Vol. 35, No. 1, 155-164, Jan. 2007.
4. Moran, D. S. and L. Mendal, "Core temperature measurement methods and current insights," Sports Medicine, Vol. 32, No. 14, 879-885, Dec. 2002.
5. Stauffer, P. R., B, W. Snow, D. B. Rodrigues, S. Salahi, T. R. Oliveira, D. Reudink, and P. Maccarini, "Non-invasive measurement of brain temperature with microwave radiometry: Demonstration in a head phantom and clinical case," The Neuroradiology Journal, Vol. 27, No. 1, 3-12, Feb. 2014.
6. Dubois, L., J.-P. Sozanski, V. Tessier, J. C. Camart, J.-J. Fabre, J. Pribetich, and M. Chive, "Temperature control and thermal dosimetry by microwave radiometry in hyperthermia," IEEE Transactions on Microwave Theory and Techniques, Vol. 44, No. 2, 1755-1761, Oct. 1996.
7. Hand, J. W., G. M. J. VanLeeuwen, S. Mizushina, J. B. Van deKamer, K. Maruyama, T. Sugiura, D. V. Azzopardi, and A. D. Edwards, "Monitoring of deep brain temperature ininfants using multi-frequency microwave radiometry and thermal modelling," Physics in Medicine and Biology, Vol. 46, No. 7, 1885-1903, Apr. 2001.
8. Arunachalam, K., P. F. Maccarini, V. De Luca, F. Bardati, B. W. Snow, and P. R. Stauffer, "Modeling the detectability of vesicoureteral reflux using microwave radiometry," Physics in Medicine and Biology, Vol. 55, No. 18, 5417-5435, Sept. 2010.
9. Snow, B. W., K. Arunachalam, V. De Luca, P. F. Maccarini, Ø. Klemetsen, Y. Birkelund, T. J. Pysher, and P. R. Stauffer, "Non-invasive vesicoureteral reflux detection: Heating risk studies for a new device," Journal of Pediatric Urology, Vol. 7, No. 6, 624-630, Dec. 2011.
10. Skou, N. and D. Le Vine, Microwave Radiometer Systems: Design and Analysis, Artech House, Boston, 2006.
11. Woodhouse, I. H., Introduction to Microwave Remote Sensing, CRC Press, Taylor &Francis Ltd., Florida, 2006.
12. Ulaby, F. T., R. K. Moore, and A. K. Fung, Microwave Remote Sensing: Active and Passive, Volume I: Fundamentals and Radiometry, Artech House, USA, 1986.
13. Balanis, C., Antenna Theory: Analysis and Design, JohnWiley & Sons, Inc., Hoboken, New Jersey, 2005.
14. Orfanidis, S. J., Electromagnetic Waves and Antennas, Rutgers University, 2016.
15. Birkelund, Y., Ø. Klemetsen, S. K. Jacobsen, K. Arunachalam, P. Maccarini, and P. R. Stauffer, "Vesicoureteral reflux in children: A phantom study of microwave heating and radiometric thermometry of pediatric bladder," IEEE Transactions on Biomedical Engineering, Vol. 58, No. 11, 3269-3278, Nov. 2011.
16. Leroy, Y., B. Bocquet, and A. Mamouni, "Non-invasive microwave radiometry thermometry," Physiological Measurement, Vol. 19, 127-148, Dec. 1998.
17. Report SFCG 34-2R2, Global RFI surveyon earth exploration-satellite service L-band Sensors (activeand passive), Sept. 2017.
19. Gabriel, S., R. W. Lau, and C. Gabriel, "The dielectric properties of biological tissues: II. Measurements in the frequency range 10 Hz to 20 GHz," Physics in Medicine and Biology, Vol. 41, No. 11, 2251-2269, Nov. 1996.
20. Bonds, Q., T. Weller, B. Roeder, and P. Herzig, "A Total Power Radiometer (TPR) and measurement test bed for non contact biomedical sensing applications," Proceeding IEEE Wireless Microwave Technology Conference, 2009.
21. Popovic, Z., P. Momenroodaki, and R. Scheeler, "Toward wearable wireless thermometers for internal body temperature measurements," IEEE Communications Magazine, Vol. 52, No. 10, 118-121, Oct. 2014.
22. Momenroodaki, P., W. Haines, M. Fromandi, and Z. Popovic, "Noninvasive internal body temperature tracking with near-field microwave radiometry," IEEE Transactions on Microwave Theory and Techniques, Vol. 66, No. 5, 2535-2545, May 2018.
23. Kummer, W. H., A. T. Villeneuve, and A. F. Seaton, "Advanced microwave radiometer antenna system study," Technical Report, NASA, USA, Aug. 1976.
25. Rodrigues, D. B., P. F. MaccarinS. Salahi, E. Colebeck, E. Topsakal, P. J. S. Pereira, P. Liamo-Vieira, and P. R. Stauffer, "Numerical 3D modeling of heat transfer in human tissues for microwave radiometry monitoring of brown fat metabolism," Proceeding of the SPIE, Vol. 8584, Feb. 2013.
26. Hasgall, P. A., F. Di Gennaro, C. Baumgartner, E. Neufeld, B. Lloyd, M. C. Gosselin, D. Payne, A. Klingenbock, and N. Kuster, IT’IS Database for thermal and electromagnetic parameters of biological tissues, Version 4.0, May 2018, www.itis.swiss/database.
27. Cuddy, J. S., W. S. Hailes, and B. C. Ruby, "A reduced core to skin temperature gradient, not a critical coretemperature, affects aerobic capacity in the heat," Journal of Thermal Biology, Vol. 43, 7-12, Apr. 2014.